Comparison of environmental impact assessment between irrigated and rainfed wheat using the life-cycle assessment method (LCA): The case of Khorramabad, Iran

The life-cycle assessment of two irrigated and rainfed wheat crops was investigated in this study. Tillage, planting, irrigation, fertilization, pesticide spraying, and harvesting are the basic stages of production for each crop throughout its life cycle. A farmer's questionnaire was used to collect farm data. The ecoinvent models compile emissions in their reports. The functional unit is designed to produce one ton of grain. Following the calculation, emissions from each stage of production in a triple environment (soil, water, and atmosphere) are logged. Following that, a life-cycle impact assessment, or LCIA, was carried out. The environmental effects were first estimated separately for each crop, followed by a comparison of the two crops. The calculated potential for each ton of irrigated wheat equals 860 Kg of CO2 equivalent in the impact assessment of global warming, whereas it is 623 Kg for rainfed wheat. The production potential per ton for the eutrophication phenomenon is roughly equivalent for both systems: 2.625 equivalent Kg po4 for irrigated wheat and 2.601 for rainfed wheat. The data from the long-term scenario show an increase in the potential for eutrophication in both crop productions. Meanwhile, the long-term effects of chemical fertilizer use on human health and aquatic and terrestrial ecosystems indicated a potential increase in their use. Following a data uncertainty analysis, it was determined that, with a confidence interval of 95 percent, details of the life-cycle assessment results could be applied to the farms under consideration. However, some of the environmental impacts in the uncertainty analysis overlap. The highest overlapping values are insufficient to call average farm results into question.